Locate and then click the following registry key: HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Security\OutlookSecureTempFolder
On the Edit menu, click Modify, and then add the following registry value: Value data: <Path/name of folder that you want to use>
Note: You may have to manually create this registry key if it does not already exist on the system.
If Outlook is installed on a terminal server, use the following registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Terminal Server\Install\Software\MICROSOFT\Office\9.0\Outlook\SECURITY\OutlookSecureTempFolder
Outlook 2003
Create a folder on C:\ called temp0
Click Start, click Run, type regedit, and then click OK.
Locate and then click the following registry key: HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Security\
In the right pane, double-click OutlookSecureTempFolder.
In the Value Data field, type C:\temp0\ and then click OK.
Exit Registry Editor.
Restart the computer.
Outlook 2010
Click My Computer, and then double-click drive C.
On the File menu, click New, and then click Folder.
Name the folder temp0.
Click Start, click Run, type regedit, and then click OK.
Locate and then click the following registry key: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security\
In the right pane, double-click OutlookSecureTempFolder.
In the Value Data field, type C:\temp0\ and then click OK.
Outlook 2000
Note: You may have to manually create this registry key if it does not already exist on the system.
If Outlook is installed on a terminal server, use the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Terminal Server\Install\Software\MICROSOFT\Office\9.0\Outlook\SECURITY\OutlookSecureTempFolder
Outlook 2003
Outlook 2010